Drill head for wing cutters



Nov. 10, 1959 c. w. KANDLE 7 2,912,228

DRILL HEAD FOR WING CUTTERS Filed July 5, 1957 2 Sheets-Sheet 1INVENTOR. CHARLES W. KANDLE' ATTORNEYS Nov. 10, 1959 c. w. KANDLE DRILLHEAD FOR WING CUTTERS '2 Sheets-Sheet 2 Filed July 5, 1957 /"L" WW4!1NVENTOR. CHARLES w. KANDLE flilag lewlum ATTORNEYS United States PatentDRILL HEAD FOR WING CUTTERS Charles W. Kandle, La Grange Park, Ill.

Application July 5, 1957, Serial No. 670,275

1 Claim. (Cl. 255-76) This invention relates to drilling apparatus andmore particularly to drill head's having wing'cutters thereon. I

In drilling vertical holes in the earth for the installation ofcaissons, large diameter concrete pipes, on the order of 48 inches, forexample, are inserted in the hole immediately after the drill head. Thedrill drive shaft extends through the concrete pipe and when the hole iscompleted the drill head is withdrawn back up through the pipe. Thedrill head, must cut a hole of larger diameter than the outside diameterof the pipe to permit the latter to be inserted after the drill head andas it progresses through the earth. Therefore, wing cutters are employedon the drill head which extend radially outwardly beyond the outersurface of the pipe, which often have a wall thickness of 6 inches.These wing cutters ream the hole clean so as to prevent binding of thepipe as it follows the drill head in the earth.

When the drilling operation is completed, the wing cutters are retractedas the drill head rotation is reversed and the drill unit can then bepulled back through the pipe.

When drilling as above described, it will be appreciated thatconsiderable weight of the drill unit is placed on the drill head and onthe wing cutters. It has been found that the resulting pressure betweenthe bottom of the hole and the drill head has caused the wing cutters tobind and prevent their swinging to a fully extended cutting position.

In accordance with this invention there has been provided a drill headincluding wing cutters which eliminates any binding of the cutters andthereby insures proper operation thereof.

Other advantages of the invention will appear hereinafter as thisdisclosure progresses, reference being had to the accompanying drawingsin which:

Figure 1 is a vertical sectional view through a hole being dug by adrill head embodying the invention;

Figure 2 is a perspective view of a drill head made in accordance withthe invention, taken generally from the bottom of the head, and showingthe wing cutters in the cutting position;

Fig. 3 is a bottom view of the head with the cutters in the contractedposition and shown in the cutting position in broken lines;

Fig. 4 is a perspective view of the top side of the head shown in Figure2;

Fig. 5 is a fragmentary view of a portion of the head, taken from thebottom side thereof and on an enlarged scale to show the recess for thecutter which is shown dotted in the contracted position;

Fig. 6 is a side view of the recessed plate portion taken along line 6-6of Figure 5; and

Fig. 7 is an elevational sectional view showing a cutter mounted on thedrill head, taken generally along line 77 of Figure 4, but with thecutter in the extended cutting position and on an enlarged scale.

Referring more particularly to Fig. 1 of the drawings, a large hole 10has been drilled in the ground 11 by the drill unit 12. The drill unitis secured to a drive shaft 2,912,228 Patented Nov. 10, 1959 areinserted in the hole fromthe top, forcing pipe 15 further into the hole.

Only two wing cutters 18, 19 are shown on the drill head of Fig. 1, butany number may be used and they would be spaced circumferentially aroundthe drill head 16. The cutters are adapted to pivot relative to head 16to a position with the outer edge thereof extending radially beyond theouter diameter of the pipe so as to form a hole slightly larger than thepipes outside diameter. The drill head is of lesser diameter than theinternal diameter of the pipe so as to permit withdrawal of the headthrough the pipe when the cutters have been retracted as shown inFigures 2 and;3.

The drill head 16 shown in Figs. 2 and 4 is comprised of a circularlyshaped heavy steel plate 17 having diametrically opposed segmentalopenings 20, 21 therein. Along the trailing edges 20a and 21a,respectively, of these openings are a series of teeth 22 which cut thebottom of the hole and a pilot drill 23 is located at the center of thehead.

Four wing cutters 24 to 27 have been shown in Figures 2, 3 and 5 andeach comprise 2 spaced apart parallel arms 28, 29 shown most clearly inFig. 7. The arms have axially aligned apertures 30 by which they arepivoted on pin 31 extending through a mating aperture 32 in plate 17.The arms 28, 29 are connected together at their other end by the cutterblade 33 welded thereto.

The periphery of plate 17 is provided with angularly spaced cut awayportions 34a as shown best in Fig. 5 to receive the individual cuttersWithin the diameter of the plate when the cutters are in the retractedor non cutting position. The leading edge 34 formed by the cut awayportion acts to limit the inward swinging of the cutter.

Adjacent the trailing edge 35 of each cut away portion 34a and on thetrailing or top side 17a of the plate 17 a reinforcing plate 36 has beenwelded. This plate serves compensate in strength for the recess 37 whichhas been cut from the opposite or leading side 17b of plate 17 adjacentto trailing edge 35. In addition the plate 36 permits the use ofstandard width cutters. That is to say, the distance between the arms28, 29 of the cutters is such as to permit the arms to slide over theplates 17, and 36 to permit free swinging of the cutters. The arms areheld against twisting when cutting by the plates therebetween. Thus, arigid cutter is provided which will not twist in use.

Rearward swinging of the cutter is limited by the cutter blade strikingthe trailing edge 35 of plate 17 and when cutting occurs a rigid thrustabsorbing support is thus provided for the blade.

The lower end of the pin 31 has a flat head and the pin has a keeper 38through its other end to hold it captive in the aligned apertures 30,32.

With this particular recessed mounting of the cutters to the head, acutting head assembly has been provided which is substantially flushacross its bottorn side in regard to the wing cutters. Stated otherwise,the wing cutters do not extend beyond the lower surface of plate 17 andrelative movement therebetween is assured to enable the cutters to swingfreely to the extended cutting position when desired. By use of thereinforcing plates 36 standard width cutters can be used without using ahead plate 17 having increased thickness over its entire areacorresponding to the thickness of plates 36. K

By recessing the wing cutters into the lower surface of the head, theWeight of the drill unit does not rest on the cutters and therefore thelatter will not bind or be retarded in their movement. The outermostedge 33a of the cutter blade may extend slightly beyond plate 17 toprovide a small blade area for engaging uncut spoil and therebyinitially swing the cutter outwardly into cutting position.

It may be desirable to make a preliminary hole with a tapered drillbefore using the drill disclosed here for the reason that a tapereddrill has faster cutting characteristics. The drill head of thisdisclosure is very efficient in reaming such a hole and for thefinishing operation therefor.

Various modes of carrying out the invention are contemplated as beingWithin the scope or" the following claim particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

1 claim:

In a Wing cutter earth drilling head having a rotary plate-like bodywith an open segment for the passage of spoil upwardly therethrough; aperipheral recess in the outer edge of said body for receiving a wingcutter blade; a second recess in the lower surface of said body andextending along and beneath the trailing edge of said peripheral recessand radially inwardly therefrom; a Wing cutter comprising a cuttingblade having its cutting edge extending radially outward of theperiphery of said body, and a cutter support carrying said blade andhaving upper and lower arms extending radially inward therefrom, thelower arm being disposed in said recesses and the upper arm being spacedabove said body; a reinforcing plate portion integral with said body andbeing disposed on the top of said body in the area coextensive with saidsec- 0nd recess to prevent distortion of the body bounding said secondrecess; and a pivot pin passing vertically through said body andreenforcing plate portion and pivotally securing the upper and lowerarms of said wing cutter thereto at the inner end of said second recess.

References Cited in the file of this patent UNITED STATES PATENTS146,752 Considine Ian. 27, 1874 147,323 Hanson Feb. 10, 1874 1,052,847Repp Feb. 11', 1913 1,858,263 Charlton May 17, 1932 1,881,101 SpauldingOct. 4, 1932 2,000,195 Siebel May 7, 1935 2,688,465 Birdwell Sept. 7,1954

